Patents by Inventor Donald W. Plass

Donald W. Plass has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6728912
    Abstract: A method for testing SOI technology memory circuits, such as in SRAMs, for weak SOI cells, uses a reset test circuit with a wordline pulse width control circuit which can be implemented without performance impact and allows using unused silicon to minimize area usage impact and permits screening of integrated SOI memory array circuits for weak SOI cells using the test reset circuit to selectively change the wordline pulse width to a reduced time while the memory cell bit select and write signals turn off at normal times to stress the cell write margin. Further, during test, the word line pulse width can be extended by blocking the reset signal of the reset path test circuit to the word path to produce a longer than normal pulse width. In addition, during a test for normal operations the reset signal is allowed to pass through a pass gate multiplexer of the reset test circuit.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: April 27, 2004
    Assignee: International Business Machines Corporation
    Inventors: James W. Dawson, Paul A. Bunce, Donald W. Plass
  • Patent number: 6584023
    Abstract: An exemplary embodiment of the present invention is a system for implementing a column redundancy scheme for arrays with controls that span multiple data bits. The system includes an array of data bits for receiving data inputs, a spare data bit and a field control input line. Also included in the system is circuitry to separate a field control signal from the field control input line into one or more individual control signals for activating a corresponding data bit in the array or for input to a multiplexor. The system further comprises circuitry to steer around a defective data bit in the array. This circuitry includes: a field control signal multiplexor corresponding to each field control signal; a spare control signal multiplexor to activate the spare data bit; a data multiplexor corresponding to each of the data bits in the array; and a spare data multiplexor to steer one of the data inputs to the spare data bit.
    Type: Grant
    Filed: January 9, 2002
    Date of Patent: June 24, 2003
    Assignee: International Business Machines Corporation
    Inventors: Paul A. Bunce, John D. Davis, Thomas J. Knips, Donald W. Plass
  • Publication number: 20020152434
    Abstract: A method for testing SOI technology memory circuits, such as in SRAMs, for weak SOI cells, uses a reset test circuit with a wordline pulse width control circuit which can be implemented without performance impact and allows using unused silicon to minimize area usage impact and permits screening of integrated SOI memory array circuits for weak SOI cells using the test reset circuit to selectively change the wordline pulse width to a reduced time while the memory cell bit select and write signals turn off at normal times to stress the cell write margin. Further, during test, the word line pulse width can be extended by blocking the reset signal of the reset path test circuit to the word path to produce a longer than normal pulse width. In addition, during a test for normal operations the reset signal is allowed to pass through a pass gate multiplexer of the reset test circuit.
    Type: Application
    Filed: April 12, 2001
    Publication date: October 17, 2002
    Applicant: International Business Machines Corporation
    Inventors: James W. Dawson, Paul A. Bunce, Donald W. Plass
  • Patent number: 4901279
    Abstract: A static random access memory cell implemented with metal Schottky field-effect transistors. The cell has first and second branches, each of the branches including: a depletion mode current limiting transistor having a drain connected to a first circuit node; a depletion mode load transistor having a drain connected to the source of the current limiting transistor and a source connected to a second circuit node; an enhancement mode active transistor having a drain connected to the second circuit node and a source connected to a third circuit node; an enhancement mode access transistor having a source connected to the second circuit node and a gate connected to the gate of the current limiting transistor; the gate of the load transistor connected to the second circuit node; the commonly connected gates of the current limiting transistor and the access transistor adapted to receive a word-line signal; and the drain of the access transistor adapted to receive a bit-line signal.
    Type: Grant
    Filed: June 20, 1988
    Date of Patent: February 13, 1990
    Assignee: International Business Machines Corporation
    Inventor: Donald W. Plass